﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace ViewComponents
{
    /// <summary>
    /// Follow steps 1a or 1b and then 2 to use this custom control in a XAML file.
    ///
    /// Step 1a) Using this custom control in a XAML file that exists in the current project.
    /// Add this XmlNamespace attribute to the root element of the markup file where it is 
    /// to be used:
    ///
    ///     xmlns:MyNamespace="clr-namespace:ViewComponents"
    ///
    ///
    /// Step 1b) Using this custom control in a XAML file that exists in a different project.
    /// Add this XmlNamespace attribute to the root element of the markup file where it is 
    /// to be used:
    ///
    ///     xmlns:MyNamespace="clr-namespace:ViewComponents;assembly=ViewComponents"
    ///
    /// You will also need to add a project reference from the project where the XAML file lives
    /// to this project and Rebuild to avoid compilation errors:
    ///
    ///     Right click on the target project in the Solution Explorer and
    ///     "Add Reference"->"Projects"->[Browse to and select this project]
    ///
    ///
    /// Step 2)
    /// Go ahead and use your control in the XAML file.
    ///
    ///     <MyNamespace:CustomControl1/>
    ///
    /// </summary>
    [TemplatePart(Name = "ValueTextBox", Type = typeof(TextBox))]
    [TemplatePart(Name = "AddButton", Type = typeof(Button))]
    [TemplatePart(Name = "SubtractButton", Type = typeof(Button))]
    public class IncrementBox : Control
    {
        private TextBox _valueTextBox;
        private Button _addButton;
        private Button _subtractButton;

        static IncrementBox()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(IncrementBox), new FrameworkPropertyMetadata(typeof(IncrementBox)));
        }

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            _valueTextBox = (TextBox)Template.FindName("ValueTextBox", this);

            _addButton = (Button)Template.FindName("AddButton", this);
            _addButton.Click += (o, e) => { _valueTextBox.Text = AddToValue(1); };

            _subtractButton = (Button)Template.FindName("SubtractButton", this);
            _subtractButton.Click += (o, e) => { _valueTextBox.Text = AddToValue(-1); };
        }

        private int Value
        {
            get
            {
                string text = _valueTextBox.Text;
                return text == string.Empty ? 0 : Convert.ToInt32(text);
            }
        }

        private string AddToValue(int numberToAdd)
        {
            int currentNumber = Value;

            int newNumber = 0;
            if (!(currentNumber + numberToAdd < 0 && !IsRelative))
                newNumber = currentNumber + numberToAdd;

            return newNumber.ToString();
        }

        public static DependencyProperty IsRelativeProperty = DependencyProperty.Register("IsRelative", typeof(bool), typeof(IncrementBox));

        public bool IsRelative
        {
            get { return (bool)GetValue(IsRelativeProperty); }
            set
            {   
                SetValue(IsRelativeProperty, value);
            }
        }
    }
}
